Radio tuning device



June 22 ,.1926. 1,589,945

E. GDDANIELSON RADIO TUNING DEVICE Filed May 19. 1925 FIIS ;L

Patented June 22, 1926.

UNITED "STATES 1,589,946 PATENT OFFICE.

ERNEST G. D ANIELSON, 01 SAN FRANCISCO, CALIFORNIA, ASSIGNOB TO B. '1. CUN- NINGm, OF SAN FRANCISCO, CALHORNIA.

RADIO TUNING DEVICE.

Application filed Kay 19, 1925. Serial No. 81,288.

This invention relates to a device for tuning radio frequency circuits, and more particularly to a device whereby a plurality of circuits can be tuned simultaneously. One form of such a device is described and claimed in a pending application, Serial Number 21,569 filed April 8, 1925 in the name of Roger M. Wise, and assigned to the same assignee as the present application.

It is one of the objects of my invention to improve in general the a construction and operation of the device disclosed in said Wise application.v The device therein disclosed is applied to a plurality of variable condenser structures, which in accordance with the invention, could be simultaneously varied by the aid of a single controlling member; and further, individual and independent tuning of each condenser could also be accomplished. Such devices are of use for example in radio rece tion, where there may be several stages. 0 radio frequency amplification, in which the associated circuits are all to be tuned to a carrier wave. A common control in which there are no provisions for individual fine adjustment of thetuning elements has been proposed, but the disadvantages of such a scheme have been carefully outlined in the said Wise application. Accordingly there is disclosed a scheme whereby it is possible to tune the circuits roughly by a slmultaneous operation, and then to tune them finely in an inde ndent manner.

1th the aid of my'present invention, substantially similar results are obtained, but by the aid of difierent mechanism. One advantage of m appzratus is that it can with great facility "placed on a panel evenjby an inexperienced person; another advantage is that the fine tunin is accomplished in such manner that t era is no danger of disturbing the rough tuning already performed. v

My 'nvention' possesses other advantageous features, some of which with the foregoing, will be set forth at length in the following description, where I shall out line in full that form of the invention which I have selected for illustration in the drawings accompan ing and forming part of-the present speci cation. Although I have shown in the drawings but one embodiment of my invention, I do not desire to be limited thereto, since the invention as defined in the claims may be embodied in other forms also.

Referring to the drawings:

Figure 1 is a rear portion of a panel on which a pair of condensers are mounted, and which embody my invention;

Fig. 2 is a top lan view of the con densers illustrated in Fig. 1, with some of the parts in section; and I Fig. 3 is a section taken on the line 33 of Fig. 2.

In the present instance I illustrate the invention asapplied to condensers built in accordance with the disclosure in a prior application filed July 26, 1924, in the name of Roger M. Wise, entitled Variable con-- This plate is mostconveniently made from sheet metal and has a turne -up edge 15 to provide rigidity. The plate may be fastened to the back of panel 11, as by the aid of a pair of screws 16 passing through the panel and tapping into the plate 14. The condenser structure 12 has a su porting disc 17 ofdnsulation material, whic is fastened upon plate 14 by the aid of a plurality of screws 18. These screws have their heads accommodated in de ressions formed in that face of plate 14 w ich is contacting with the rear of panel 11, whereby these heads do not interfere with the plate mounting. Projections such as 19 extend from the disc 17 and serve not only to provide tap (1 holes for screws 18, but also to s ace the and the structure carried there y from the plate 14. This structure includes the movable sets of condenser plates 20 and 21, which are arranged to overlap to any desired extent between limits. To support these sets of plates, a pair of stationary rods or studs 22 and 23 is provided, which studs arerigidly fastened at one end to disc 17 in the projections 24 on this disc. A series of brass spacers 25 is-passed over each stud, and the plates 20 and 21 have ears 26 that are passed over the studs between the spacers. The ears are each soldered to the spacers, which are so arranged that plates 20 and 21 can be made to interleave without interference from each other.

The spacers 25 and plates 20 and 21 are mounted for rotation on studs 22 and 23, and for producing this rotation, gears 27 and 28 are fastened to the inner end spacers respectively. These gears, which intermesh, are preferably made from insulation material, and are journalled for rotation on studs 22 and 23. In order to hold the sets of plates 20 and 21 against axial removal, and for providing a stiffening member, a strip 29 of insulation is placed between the studs 22 and 23, and binding post structures 30 are used to hold the strip and the plate assemblies together. It is evident that rotation of one or the other of the pair of gears 27, 28 will produce relativemovement of the sets of plates, whereby they may be interleaved to any desired extent.

' In order to keep the plate structure rigid and to ensure that all of the plates of each set are in good electrical connection with each other, each of'the plates is provided with an ear 31 at the top, and another car 32 at the bottom; all of the ears 31 and 32 of all of the lates are bent so that each overlaps the a jacent ear of the next plate in the set, and are joined as by soldering. The result is that the ears of a series form practically a solid bar, such as 33, connect-' ing all of the plates of a set. Furthermore, each binding post structure 30 includes a terminal 34 having cars by the aid of which connections can be made to a circuit, and to which pigtail connections such as 35 may lead from the associated plate assembly 20 or 21.

Suficient friction is provided in the moving parts, as is customary, to ensure that the condenser lates can be retained in any relative position until it is desired to change the setting.

The operation of gears 27 and 28, and consequently of the plates 20 and 21 is effected in this instance by the aid of a small pinion 36 meshing with gear 27 This pinion has a shaft 37 extending through a bushing 38 fastened to plate 14, as well as through the panel 11 and the disc 17. At the free extremity and on the fnont side of the panel 11, the shaft carries any well-known form of tuning dial 39, having a knob 40 for manual control. It is evident that manipulation of dial 39 by the aid of knob 40 causes a corresponding rotation of gears 27 and 28. The pinion 36 is held against removal by the aid of a forked member 41 of thin metal straddling the shaft 37 n the rear side of the disc 17. This member is held in place by a screw42 engaging the disc 17, as well as by a projection 43 entering into an aperture 44 in this disc.

In order to limit the extent of movement Leeaeae been somewhat detailed, but only forthe purpose of providing one example of the kind of apparatus with which my invention can be utilized. In the present instance, both sets of condenser plates are movable; but it is evident that. other well-known forms of condenser structure. could be utilized, in which one set of plates is-stationary.

With the type of condenser disclosed, however, it becomes a simple matter to provide another similar condenser structure such as 13 which can be adjusted by the aid ofthe same knob 40 simultaneously with the adjustment ofcondenser 12. All that it is,

necessary to do is to intermesh the adjacent gears 28 and 48 of the condenser structures. When this is done, it is evident that all of the gearing is rotated by rotation of pinion 36. Of course in the condenser structure 13, there is no equivalent to this pinion.

The arrangement as now described is such that both condensers 12 and 13 are adjusted in unison. In accordance with my invention, it is possible to impart a supplementary movement in either direction to one of the sets of plates on the condenser 13, whereby the slight irregularities of the two radio frequency circuits associated with the condensers, may be compensated for. This result can be accomplished by imparting a planetary motion to gear 48 about the axis of gear 28; or alternatively, by imparting a planetary motion to gear 49 that meshes with gear 48, about the axis of gear 48. The

structure disclosed shows the latter alternative. It is evident that when gear 49 rolls on the periphery of gear 48, the set of plates 50 associated with gear 49 will be rotated with respect to the other set of plates 51. In this way, by proper extent of the planetary motion of gear 49, any desired supplementary adjustment in either direction, can be imparted to condenser 13. To permit this planetary movement, use is made of a fiat plate support 52 which has a pivot pin 53 passing through plate 14 as Well as through the support 52. 'This pin .has an axis coincident with that of gear 48, whereby oscillation of support 52 will cause the tary support for pin 53 is provided bya strip 54, fastened at one end to plate 14, as

by the rivets 55. The plate 14 is of course provided with depressions where the Various screws or rivets, such as 55 and 5 3,"pass through it, whereby -the'lieads 'of these panel 11.

The support 52 is urged to rotatein et,

clockwise direction, as viewed in Fig. 1,

the aid of a spring 56, which if free to act would'of course cause the set of plates to recede from between the other set 51. The sprin edge 15 o plate 14, and at the other end, it is fastened. to an ear piece 57 which is clamped between plate 52 and one of the bosses 58 formed on the back of the disc 59 upon which condenser 13 is mounted. In order to limit the extent to which spring 56 can oscillate plate support 52, mechanism is provided for opposing the action of the spring. Thus for example, a rotatable cam 60 is provided, which coacts with an extension 61 formed in this instance integrally with the support 52. The cam 60, as disclosed mostclearly in Fig. 3, is fastened to a short shaft 62 passing through a bushing 63 formed in plate 14. This bushing in turn extends into an aperture in panel 11. A knob 64 is fastened to shaft 62 and is available for manual manipulation from the.

front of panel 11. In order to make it possible to maintain cam 60 in any desired position, a spring strip 65 is interposed between cam 60 and plate 14, whereby a frictional force exists between this cam and the strip 65. The, cam 60 also carries an extension 66 which limits its rotation in one direction by abutting against -the projection 61.

The mode of o eration of my invention is evident from tlie' fore ing description. Rough tuning is accomp ishe'd'by rotation of knob 40. Then knob 64 can be rotated to any desired extentto provide a fine adjustment of condenser 13. Then knob 40 can if desired be further adjusted for fine adjustment of condenser 12, and the process repeated until both condensers are as accurate.

In the present instance a bank of only two condensers is disclosed. It is possible nevertheless to extend the idea to any number of condensers, by a continued succession of mountings, similar to that already described. Furthermore, if only three condensers are to be thus controlled, it is possible to mount 56 is anchored at one end to the a support such as 52 on the axis coincident with that of its ri t hand gear, meshing with 27 of con enser 12, whereby there woul be substantially a symmetrical arrangement of the three condensers.

I claim:

1. In a device of the class described, a plurality of electrical instruments each havmg a rotatable shaft, means for mounting said instruments'in side by side relationship with said shafts substantially parallel, a gang control for said instruments, and means including a cam for causing relative displacement between certain of said shafts in a plane substantially normal to said shafts to control one instrument independently of the others.

2. In combination, a plurality of variable condensers each having a pair of relatively movable plate structures, a common means for causin simultqmeous relative movement of all of t e plate structures of all of the condensers, and means for independently causing relative movement of all of the plate structures of at least one of the condensers, comprising a rotatable cam.

3. In combination, a plurality of variable condenser structures, each having a pair of relatively movable plate structures, said condenser structures including intermeshing gears connected. together whereby all of the pairs of plate structures can be operated simultaneously, and means whereby one of the gears of one of the condensers can be independently rotated, comprising an oscillatable support for one of the condensers ivoted on an axis common to thatof one 0 its denser structures including intermeshing gears connected together whereby all of the pairs of plate structures can be operated simultaneously, and means whereby one of the gears of one of the condensers can be independently rotated, comprising an oscillatable support for one of the condensers pivoted on an axis common to that of one of its gears, and a cam for adjusting the position of said support on its axis.

5. In combination, a plurality of variable I condenser structures, each having a pair of relatively movable plate structures, said condenser structures including intermeshing gears connected together whereby all of the pairs of plate structures can be operated si-,

multaneously, and means whereby one of the gears of one of the condensers can be independently rotated, comprising an oscillatable support for one of the condensers pivoted on an axis common to that of one of its gears, a resilient means for urging said support in one direction about its pivot, and an adjustable cam for moving the support in the opposite direction.

6. In combination, a plurality of variable tuning devices, each of said devices having a movable stnncture for varying its electrical characteristic, as Well as a gear mechanically connected to the structure whereby they move in unison, all of said gears intermeshing, an oscillatable support for one of said 10 s1 ructures, pivoted on an axis common with that of one of the pears, the movable structures being SlIIlll taneously operated by movement of any of the gears, and a cam for imparting a planetary movement to at least one of the gears, by oscillating said support, for independently rotating the associated movable structure. I

In testimony whereof, I have hereunto set my hand.

ERNEST G. DANIELSON. 

